JP5798984B2 - Pressure sensor device - Google Patents

Description

  The present invention relates to a pressure sensor device mounted on an exhaust system of an internal combustion engine.

  In an internal combustion engine of a diesel engine, exhaust particulates (hereinafter referred to as PM) contained in exhaust gas discharged from the main body of the internal combustion engine has become a problem, and a diesel particulate filter (hereinafter referred to as DPF) that collects PM. ) Is required mainly in Europe, where the penetration rate of vehicles equipped with diesel engines is high. In the DPF, when a certain amount of PM is collected, the DPF itself is heated to burn the collected PM. The amount of PM collected by the DPF can be estimated from the pressure difference between the upstream side and the downstream side of the DPF. In this way, the DPF is prevented from being clogged with PM. Therefore, when the DPF is mounted, it is necessary to install a pressure sensor device that detects the pressure on the upstream side and the downstream side of the DPF.

  As a circuit board mounting method of the pressure sensor device, for example, there is an invention described in Patent Document 1.

JP 2000-28458 A

  In the case of wire bonding, it is preferable that the variation in the height direction of the circuit board is small in order to improve the connection strength. In Patent Document 1, a circuit board 7 on which a sensor signal processing circuit is formed is bonded and fixed to the back side of a sensor chip case, and a signal from the sensor chip is input to the processing circuit via a bonding wire 6. It is disclosed. According to Patent Document 1, the sensor signal processing circuit board is directly bonded and fixed to the sensor chip case. The sensor chip case is adhesively fixed to the housing with an adhesive so as to hermetically separate the pressure introducing chambers 11a and 11b. Since it is necessary to bond with a certain amount of adhesive to adhere to airtight separation using an adhesive, the sensor chip case is easily affected by the adhesive. Variation in the height direction becomes large. That is, Patent Document 1 leaves room for study on reducing variations in the height direction of the circuit board.

  An object of the present invention is to improve the connection strength of wire bonding.

In order to solve the above problem, the pressure sensor device of the present invention, before Symbol housing, the upper side of the first and second pressure sensing elements, provided a base member, and a circuit board, said base member The circuit board is bonded and held by an adhesive, and the housing has a holding portion for mounting the base member on the upper side of the first and second pressure detection elements, and the base The member is bonded and fixed to the holding portion of the housing by an adhesive.

  According to the present invention, the connection strength of wire bonding can be improved.

The diesel engine block diagram of the internal combustion engine which shows one Example of this invention. (A) Top view showing one embodiment of the present invention (b) AA sectional view showing one embodiment of the present invention. (A) Top view showing one embodiment of the present invention (b) AA sectional view showing one embodiment of the present invention.

Hereinafter, an embodiment for carrying out the present invention will be described.
FIG. 1 shows the overall configuration of a diesel engine that is an internal combustion engine provided with the pressure sensor device of the present invention.

  A turbocharger 3 and a DPF 4 are provided in the exhaust passage 2 connected to the exhaust port of the internal combustion engine 1. The pressure sensor device 5 detects the pressure in the exhaust passage 6 via pressure introducing pipes 7 and 8 such as hoses. The pressure sensor device 5 detects the pressure on the upstream side and the downstream side of the DPF 4, the signal corresponding to the absolute pressure on the upstream side of the DPF 4, the signal corresponding to the absolute pressure on the downstream side of the DPF 4, the upstream side of the DPF 4 and A signal corresponding to the differential pressure between the downstream pressures is output to the ECU 9.

  The ECU 9 determines whether the DPF 4 is clogged based on the differential pressure detected by the pressure sensor device 5. If it is determined that the DPF 4 is clogged, the trapped PM is burned by raising the DPF 4 to a high temperature to eliminate the clogged state.

  An air flow sensor 11 is installed in the intake passage 10 to detect the amount of intake air. The intake passage 10 is provided with an intercooler 12 and an intake throttle valve 13 and communicates with the intake manifold 14.

  Further, an exhaust gas recirculation passage 15 communicates with the exhaust passage 2, and an EGR cooler 16 and an exhaust gas recirculation passage throttle valve 17 are provided.

  The ECU 9 determines whether the DPF 4 is clogged based on the differential pressure detected by the pressure sensor device 5. If it is determined that the DPF 4 is clogged, the trapped PM is burned by raising the DPF 4 to a high temperature to eliminate the clogged state.

  An air flow rate measuring device 11 is installed in the intake passage 10 to detect the intake air amount. The intake passage 10 is provided with an intercooler 12 and an intake throttle valve 13 and communicates with the intake manifold 14.

  Further, an exhaust gas recirculation passage 15 communicates with the exhaust passage 2, and an EGR cooler 16 and an exhaust gas recirculation passage throttle valve 17 are provided.

  The ECU 9 receives output signals from the pressure sensor device 5 and the air flow rate measurement device 11 and output signals from various sensors (not shown) so as to be informed of the state of each part.

  The product of the present invention is a pressure sensor device that detects upstream and downstream pressures of a DPF 4 that collects exhaust particulates installed in an exhaust system of a diesel engine through pressure introduction pipes 7 and 8 such as hoses. With one pressure sensor device, it is possible to detect the absolute pressure output on the upstream side and downstream side of the DPF 4 and the pressure difference between the upstream side and downstream side of the DPF 4 to determine the clogged state of the DPF 4.

A first embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 2, the pressure sensor device according to the first embodiment of the present invention includes a housing 18 having a connector terminal 22, an upstream pressure introduction passage 25, a downstream pressure introduction passage 26, and a mounting portion 19, and a housing Intermediate terminals 23, 24 inserted into 18, pressure detection elements 27, 28 provided in the housing 18, a base member 21 provided on the pressure detection elements 27, 28, and a base member 21. Sensor circuit board 20 and cover 29.

  An upstream pressure detecting element 27 for detecting the pressure on the upstream side of the DPF 4 and a downstream pressure detecting element 28 for detecting the pressure on the downstream side of the DPF 4 are bonded to the housing 18 by an epoxy adhesive A31.

  In order to prevent gas and the like from entering the housing 18 from the pressure introduction passages 25 and 26, the pressure detection elements 27 and 28 and the epoxy adhesive A31 are hermetically separated.

  The upstream pressure detection element 27 and one end of the intermediate terminal 23 are electrically connected by welding or the like, and the downstream pressure detection element 28 and one end of the intermediate terminal 24 are electrically connected by welding or the like.

  The sensor circuit board 20 is bonded to the base member 21 formed of a resin material by an epoxy adhesive B32. In the housing 18, a base member holding portion 37 is formed above the pressure detection elements 27 and 28. Here, the upper side refers to the arrow direction of the Z axis in FIG. The base member 21 on which the circuit board 20 is mounted is bonded to the base member holding portion 37 of the housing 18 with an epoxy adhesive B33. As a result, the circuit board 20 is configured not to touch the pressure detection elements 27 and 28 directly.

  In the present invention, the circuit board is not directly mounted on the pressure detection elements 27 and 28, but the circuit board is mounted on the base member 21, and the base member 21 and the housing 18 are bonded and fixed with the epoxy adhesive B33. It has become. Adhering and fixing the base member 21 to the housing 18 does not require an amount of adhesive that allows the housing 18 and the pressure introducing passages 25 and 26 to be hermetically separated from each other, thereby reducing the influence of the adhesive. it can. Therefore, variations in the height direction of the circuit board can be reduced, and the strength of wire bonding can be improved.

  Since various electronic components are mounted on the sensor circuit board 20, a silicone gel 35 is applied for protection. In order to protect the sensor circuit board 20 and the wire bonding 30 from contamination, moisture, etc. in the mounting environment, the cover 29 is bonded to the housing 18 with an epoxy adhesive 34.

  The connector terminal 22 and the sensor circuit board 20 are electrically connected by wire bonding 30, and the other end of the intermediate terminal 23 and the sensor circuit board 20 are electrically connected by wire bonding 30. The ends and the sensor circuit board 20 are electrically connected by wire bonding 30.

  The intermediate terminals 23 and 24 are inserted into the housing 18, and the pressure detection elements 27 and 28 are connected to the sensor circuit board 20 via the intermediate terminals 23 and 24, respectively. Therefore, the sensor circuit board 20 is connected to the pressure detection elements 27 and 28. It can be arranged at the top of, ie, a hierarchical structure. By arranging the pressure detection elements 27 and 28 in the longitudinal direction of the sensor circuit board 20 and providing the sensor circuit board 20 above the pressure detection elements 27 and 28, the horizontal space can be used effectively, and the horizontal size of the pressure sensor device can be reduced. Can be realized.

  Using two pressure detection elements 27 and 28, the absolute pressures of the upstream and downstream pressures of the DPF 4 are measured, and the clogged state of the DPF is detected. Therefore, if the hose connected to the downstream side of the DPF 4 is mistakenly connected to the upstream pressure introduction passage 25, the upstream pressure detection element 27 detects the pressure on the downstream side of the DPF 4, and the clogged state of the DPF 4 is normal. It becomes impossible to judge. Therefore, in order to prevent erroneous insertion of the hose, the upstream pressure introduction passage 25 and the downstream pressure introduction passage 26 have different diameters so that the upstream pressure introduction passage and the downstream pressure introduction passage can be easily determined.

  Further, since the air on the upstream side of the DPF 4 contains more foreign matters such as PM than on the downstream side, the diameter of the upstream pressure introduction passage 25 is increased to prevent clogging of the pressure introduction passage due to foreign matters. In particular, if the inner diameter of the upstream pressure introduction passage 25 is set to 5.5 mm or more, water that has entered the pressure introduction passage can be prevented from stretching a water film, so that clogging of the pressure introduction passage can be effectively prevented.

A second embodiment of the present invention will be described with reference to FIG.
A pedestal 36 is provided on the bottom surface of the base member 21. The circuit board 20 is mounted on the base member 21 by filling the adhesive 32 in a region recessed when viewed from the pedestal 36. Thereby, since the circuit board 20 is suppressing the dispersion | variation in the height direction in the base part 36, the connection strength of the wire bonding 30 can be improved.

  Further, as a layout of the pedestal portion 36, when the circuit board is mounted on the base member, the pedestal is preferably arranged at the wire bonding portion of the circuit board. Since the pedestal is located under the wire bonding portion, it is possible to suppress the occurrence of height variation during wire bonding, and the connection strength of wire bonding can be further improved.

  Further, the pedestal 36 is preferably provided at the bottom of the base member 21 so as to be 180 degree rotationally symmetric. By adopting a 180 degree rotationally symmetric layout, variations in the height direction can be suppressed, and the connection strength of wire bonding can be improved. Further, by adopting a 180-degree rotationally symmetric layout, there is no attachment direction when attaching the circuit board 20 to the base member, there is no confirmation process of the attachment direction at the time of manufacture, and the work of attaching the circuit board 20 to the base member 21 is eliminated. Simplified. This is particularly effective when the layout is such that the pedestal 36 is disposed at the wire bonding location of the circuit board 20 in order to suppress height variations during wire bonding.

1 Internal combustion engine 2, 6 Exhaust passage 3 Turbocharger 4 DPF
5 Pressure sensor device 7 Upstream pressure introduction pipe 8 Downstream pressure introduction pipe 9 ECU
DESCRIPTION OF SYMBOLS 10 Intake passage 11 Air flow measuring device 12 Intercooler 13 Intake throttle valve 14 Intake manifold 15 Exhaust recirculation passage 16 EGR cooler 17 Exhaust recirculation passage throttle valve 18 Housing 19 Mounting part 20 Sensor circuit board 21 Base member 22 Connector terminals 23, 24 Intermediate terminal 25 Upstream pressure introduction passage 26 Downstream pressure introduction passage 27 Upstream pressure detection element 28 Downstream pressure detection element 29 Cover 30 Wire bonding 31 Epoxy adhesive A
32, 33 Epoxy adhesive B
34 Epoxy adhesive C
35 Silicone gel 36 Base part 37 Base member holding part

Claims (4)

A housing having a first pressure introduction passage, a second pressure introduction passage, and a connector portion;
A first pressure detecting element provided in the housing for detecting the pressure introduced from the first pressure introduction path;
A second pressure detection element provided in the housing for detecting the pressure introduced from the second pressure introduction path;
With
In the pressure sensor device in which the first and second pressure detection elements are fixed inside the housing with an adhesive, whereby the first and second pressure introduction passages and the inside of the housing are separated in an airtight manner .
In the housing, a base member and a circuit board are provided above the first and second pressure detection elements,
The base member holds the circuit board bonded with an adhesive,
The housing has a holding portion for mounting the base member on the upper side of the first and second pressure detection elements,
The pressure sensor device according to claim 1, wherein the base member is bonded and fixed to the holding portion of the housing by an adhesive.
The pressure sensor device according to claim 1,
The base member has a plurality of pedestal portions. The pressure sensor device according to claim 2,
The pedestal portion provided on the base member is formed at a portion corresponding to a wire bonding connection portion of the circuit board when the circuit board is mounted on the base member. The pressure sensor device according to claim 2,
The pressure sensor device is characterized in that a layout of the pedestal portion is 180-degree rotationally symmetric.